I have seen 3 different part numbers listed for a 2006 prius abs actuator assembly... 44500-47141 - Found one of these available "new" for sale by a dealer online, with resistor, but Toyota's site lists them as no longer in production... 44510-47050 - The model number present on my 2006 Prius that is failing, also 90% of the used ones have this model number, PLENTY out there used for $400-500, but likely the same issues. Does not seem like the one to get. 44510-47051 - Appears to be the "updated" model based on used descriptions, but Toyota parts sites do not even have it. The search pulls up nothing... Is there a part number I am missing? Why would Toyota stop selling this when so many of them fail? I just want to find the best option for replacement before spending $500-1500 into it. What are other people buying?
A part can very often have a yyyyy-zzzzz number stamped on it that is not its part number, even though it looks just like one. I noticed the same thing years ago with Ford numbers. Frustrating. The number can be an "engineering" number, or it might be the number of some non-separately-available part of the assembly, that happens to be visible on the assembled unit. That seems to be what's going on here. On the drawing, the PNC 44510 is used to refer to the brake actuator, but the actual parts that were sold had the prefix 44500, not 44510. They were 44500-47140 and 44500-47141, both now out of production. When listings with 44510- "part numbers" are seen on the internet, those are likely to be from sellers of used parts who do not know the actual part number of the unit they are listing, and they list it under the 44510- number they can read off the part, which isn't its part number. Those used units are probably the 44500-47140 or 44500-47141 parts. A person could guess that maybe the ones with 44510-47050 readable on them were the older, 44500-47140 part, and the ones with 44510-47051 readable on them were the later, 44500-47141 part. But that would be a guess. The youngest Gen 2 is 13 years old now. Manufacturers do stop making parts after a while.
The original part installed in a majority of Gen 2 Prius is 44510-47050 which is why you see so many used actuators with this part number. The replacement part numbers have gone through a couple of revisions.
Most likely, as explained above, that is a number found on the part that is not the part number. Sellers of used parts often will use such a number in their listings, because they don't know that it isn't the part number, and they don't know what the actual part number is.
44500-47141 is the latest part number, confirmed by dealer. It is on indefinite backorder which is why it shows "not available" online. I did find one on ebay for $750, new in the box never installed "new old stock" guy had the receipt from Toyota and everything.
So I ordered a brand new 44500-47141. The receipt shows 44500-47141. The Toyota box has 44500-47141 on the label. The part inside is labelled 44510-47051. Mystery solved? Got a good price on it... new, never used, with resistor. $750. Maybe it is not the box that came with this part, but at least it is not the original part number from 2006 so hopefully it's somehow actually been updated by Toyota.
Yeah, parts having numbers on them that aren't the part number is a real thing. Sometimes those numbers will be mentioned in the catalog listing as a "mark", but often not mentioned at all. Adds a bit of confusion, but it's just another thing to get used to.
Been wrenching on Toyotas and Lexuses for years using dealer parts and this is the first I have seen of this myself. Usually they list a superseded part number on the website. First time really digging into a Prius though!
Right, it's not a superseded part number, because it never was an orderable part number at any time. Such numbers can be factory-only part numbers for some component part of the unfinished assembly, and just happen to end up being visible when it's finished. Or they can be numbers that have their origins in engineering drawings of some kind, forever distinct from part numbers. When I first asked a Ford dealer about that (an old Ford I had was where I first noticed it) I got that sort of explanation. More can be found (in a Gen 3 thread though) here and here.